Slash lamp



`vJ. CSTERMEIER Dec, 6, 1932. FLASH LAMP i Reg. 18,678

v originan Fuga April 5. `1929 -ZYVM/ ning speed in a bulb filled withpure oxygen Reissuecl Dec. 6, 1,932

UNITED STATES PATENT FFLCE JOHANNES OSTERMEIER, 0F ALTHEGNENBERG,(zTrEIEtlltlAN'Y,` ASSIGVNOR, BY MESNE ASSIGNMENTS, TQ GENERAL ELECTRICCOMPANY, A CORPORATIONOF NEW YORK FLASH LAMP d Original No. 1,776,637,dated September 23, 1930, Serial No. 352,705, led April 5, 1929, and inGermany February 28, 1929. Application for reissue filed August 9, 1932.Serial No. 628,758.

The invention relatesvto Hash lamps, more particularly those intendedfor photographic purposes. Flash lamps are already known in which anoxidizable metal in the form of wire or ribbon or a flash mixture islodged in a as-tight transparent bulb which contains a lling of oxygen,of an oxygen-gas mixture, or of a gas that gives oft' oxygen, such as-anoxide of nitrogen as N20, at a pressure less than atmospheric. Fromthese known fiash lamps the lamp according to the invention differsbythe fact that foils of oxidizable substances, more particularly ofmetals and metal allows are used as a light producer which foils are soarranged in the bulb as to be in the range of an igniter.

Tests have proved that. foils burn away at an extremely high speed, whenthe necessary oxygen or combination is present in suficient purity andunder suitable pressure. This rapid combustion takes place if thefilling of the bulb contains the saine percentage of oxygen as containedin atmospheric air. Now, the remarkable diierence exists in thecombustion, e'. g. of aluminum foils in the free air taking place veryslowly, so to say crawlingly,while it takes place with lightunder apressure of 150 mm. Hg. As measurements have shown, in this case theaverage duration of the combustion amount to 1/40 second. The speed ofthe combustion can be increased by increasing the vpressure of theoxygen. In this case the phenomenon is to be observed that the lightningeiiect 'of the metal foil when burned in atmospheric air amounts only toone hundredth of that obtained by burning the foil in an equal quantityof pure oxygen under a pressure of 150 mm. Hg. within the bulb, 'thepressure ofV the gas in the bulb Athen being reduced in the proportionof the percentage of oxygen in the atmospheric air, that is iu theproportion of about 21 79. l

Substances well suited to be used as foils are metals7 metal alloys, andrare earths, such as aluminum, copper, iron, nickel, phosphorbronze,cerium, zirconium, and also organic substances. The combustion of thefoil may be initiated by any suitable ignitingdevice.

In order that the invention can be more easily understood, a preferredembodiment of an electrically ignited flash lamp accord-l ing to theinvention is illustrated by way of example in the drawing, which shows aside view, partly in section, of the lamp.

The lamp has the shape of a normal electric incandescent lamp. The bulbl possesses the usual glass neck 2 with a sealed-in small tube 3 servingto'draw off/the air or to fill the bulb with the gas. The conductingwires 4a, 4b are likewise sealed in the neck 2 and extend approximatelyupto the midst of the bulb. Near their upper ends the Wires 4, 4b areheld in place by means of a glass piece or rod 5 and are interconnectedat their ends by filling are the greater, the smaller the thick ness ofthe foils. The thickness ofthe metal foils amounts to about 0.0005 mm.The pressure of the oxygen in the bulb is between 12o-180 mm1 Hg.

The described lamp need not be equipped with any means :for securing itagainst explosion when the bulb happens to become leaky. This resides inthe fact that in case of leakiness of the bulb the combustion of themetal foil takes place very slowly so that a dangerous increase ofpressureis avoided due to the heat of combustion being given off to theair surrounding the lamp. The only drawback of the lamp becoming leakyis that the lamp cannot be used as a. flash lamp.

As can be seen from the foregoing, the igniting Wire 6 and thecomposition 7, if any, burn away when electric current is supplied. Theame of the combustion ignites the surrounding foil lilling-8. Of course,the lling must be within the range of the described igniter. The costsof production of the lamp are very low as the above-mentioned safetymeans may be dispensed with and the possibility is present to use verycheap foil material.

' with a gaseous oxygenic substance; an ignittight transparent of anormal pocket lamp battery is sufficient` to cause ignition. Thistherefore affords the advantage of the use of the lamp without dependingupon an electric supply system.

When used for photoglraphic purposes, the bulb may be fitted inside oroutside with a layer of a material, such as a yellow Hlter or tartrazinthat absorbs a portion of the rays ofthe spectrum of the light emitted,or the bulb itself may be made of a material, such as yellow glass,having such an absorbing effect. f

What I claim and desire to secure by Letters Patent is 1. A Hash lampparticularly for photographic purposes, comprising a closed gastighttransparent bulb containing an oxygen g as; and a foil in the bulbadapted to emit ight gen and disposed within effective range of an uponcombustion thereof with the oxyignition device.

2. A Hash lamp particularly for photographic purposes, comprising aclosed gasbulb containing an oxygen as mixture; a foil inthe bulbadapted to emit light upon combustion thereof with the oxygen anddisposed within effective range of an ignition device; and a screenassociated with the bulb for absorbinga portion of I the rays of thespectrum.

3. A Hash lamp particularly for photographic purposes, comprising aclosed gastighttransparent bulb containing a gas capable of yieldingoxygen; and a foil in the bulb adapted to emit'light upon combustionthereof with the oxygen effective range of an ignition device, said bulbbeing adapted toabsorb a portion of the rays of the spectrum.

4. A Hash lamp particularly for photographic purposes, comprising aclosed gastight bulb having a gastherein; an igniting device in said4bulb; and

a foil in the bulb adapted to emit light upon combustion there- -of withthe gas and disposed Within'eiective range of the ignition device.

-5. A flash lamp, comprising a bulb filled V with a gaseous oxygenicsubstance at a pressure less than atmospheric; an igniting device insaid bulb; foil of oxidizable substance in said bulb in the ignitionrange of said device; and a layer on said bulb of a substance adapted toabsorba portion of the rays of the spectrum.

6. A Hash lamp, comprising a bulb filled ing device in said bulb; foilof oxidizable substance in said b ulb in the ignition range of saiddevice, said bulb ignition device,

and disposed Within being of a material adapted to absorb a portion ofthe rays of the spectrum.

7. A flash lamp, comprising a bulb filled with a gaseous oxygenicsubstance; an electric vigniting device arranged in said bulb andcomprising two conductors extending tive range of an ignition device.

9. A flash lamp particularly for photoraphic purposes, comprising aclosed gas tight bulb having a gas therein; au ignition Ydevice in saidbulb; and a loose filling 'of foil in the bulb adapted to emit lightupon conibustionA thereof with `the gas and disposed Within effectiverange of tlie ignition device.

10. A Hash lamp particularly for photographic purposes, comprising ayclosed gas tight transparent bulb containing a gas at a pressuresubstantially below atmospheric and a loose filling of foil in the bulbadapted to emit light upon combustion thereof with said gas and disposedWithin effective range of an the thinness of the foil being such thatthe foil will burn with lightning speed.

In witness whereof, I have hereunto set my hand.

JOHANNES OSTERMEIER.

